HMG-CoA reductase inhibitors: design, synthesis, and biological activity of tetrahydroindazole-substituted 3,5-dihydroxy-6-heptenoic acid sodium salts
摘要:
Compounds comprising a series of 7-[2-(4-fluorophenyl)-4,5,6,7-tetrahydro-2H-indazol-3-yl]-3,5-dihydroxy-6-heptenoic acid sodium salts (18) were synthesized and tested for their ability to inhibit HMG-CoA reductase in a partially purified enzyme preparation and cholesterol biosynthesis from acetate in cultured HEP-G2 cells. Changing the size of the saturated ring of the tetrahydroindazole nucleus did not improve potency, but incorporation of substituents at the 7-position resulted in up to 1700-fold improvement in inhibitory potency. Structure-activity studies revealed that the most potent compounds possess a substituted benzyl group at the 7-position, with a preference for steric bulk at the para position of the benzene ring. The most potent enzyme inhibitor (18t, IC50 = 3.0 nM) is approximately 3-fold more potent than lovastatin sodium salt (2). The most potent cholesterol biosynthesis inhibitor in HEP-G2 cells (18q, IC50 = 0.078 muM) is slightly less potent than 2 (sodium salt). Molecular modeling studies suggested that, when compared to the parent compound (18b) lacking the appropriate 7-substituent, 18t overlaps better with 2 and literature inhibitors 5 and 6 in a hydrophobic binding region adjacent to the enzyme active site.
Palladium-Catalyzed Allylic Alkylation of Simple Ketones with Allylic Alcohols and Its Mechanistic Study
作者:Xiaohong Huo、Guoqiang Yang、Delong Liu、Yangang Liu、Ilya D. Gridnev、Wanbin Zhang
DOI:10.1002/anie.201403410
日期:2014.6.23
Allylicalcohols were directly used in Pd‐catalyzed allylicalkylations of simpleketones under mild reaction conditions. The reaction proceeded smoothly at 20 °C by the concerted action of a Pd catalyst, a pyrrolidine co‐catalyst, and a hydrogen‐bonding solvent, and does not require any additional reagents. A computational study suggested that methanol plays a crucial role in the formation of the
Highly Controlled Chemoselectivity of Tin Enolate by Its Hybridization State. Anionic Complex of Tin Enolate Coordinated by Tetrabutylammonium Bromide as Halo Selective Reagent
作者:Makoto Yasuda、Keiko Hayashi、Yasuhiro Katoh、Ikuya Shibata、Akio Baba
DOI:10.1021/ja972190s
日期:1998.2.1
bromide (Bu4NBr) to neutral four-coordinated tin(IV) enolates 1(e). The highly coordinated enolates which attained a marked change in chemoselectivity have higher nucleophilicity to organichalides. In addition, they showed low nucleophilicitytoward carbonyl moieties by the coordination of the bromide anion, whereas carbonyl addition readily proceeds using the usual four-coordinated tin enolate. NMR studies
Alkylation via tris(dialkylamino)sulfonium enolates
作者:R. Noyori、I. Nishida、J. Sakata
DOI:10.1016/s0040-4039(00)71493-6
日期:1980.1
Tris(dialkylamino)sulfoniumenolates generated from tris(diethylamino)sulfonium difluorotrimethylsiliconate and enol silyl ethers are readily alkylated by various alkyl halides under mild conditions.
Alkylation of silyl enolates with tert-alkyl or allylic fluorides proceeds smoothly in the presence of a catalytic amount of borontrifluoride to afford the corresponding carbonyl compounds. Allylation and reduction of alkylfluorides with allylsilane and hydrosilane, respectively, occur under BF3 catalysis.
Which nucleophiles are capable of attacking the allyl ligand of the Pd-stabilized allyl cation 1? This question is answered by the electrophilicity parameter of 1 which is derived from kinetic investigations.